Spray-valve for liquid-fuel engines.



P. L. SCOTT.

SPRAY VALVE FOR LIQUID FQELENGINES. APPLICATION man JUNE 18. ms.

1,%95,612u Patented Feb. 25, 1919.

fflz; z. 52,27,

I BY

PHILIP LANE SCOTT, OF SYRACUSE, NEW YORK.

SPRAY-VALVE FOR LIQUID-FUEL ENGINES.

Specification of Letters Patent.

Patented Feb. 25, 1919.

Application filed June 18, 1918. Serial No. 240,710.

To all whom it may concern:

Be it known that I, PHILIP LANE Soo'rr, residing at S racuse, in thecounty ondaga and tate of New York, have invented certain new and usefulImprovements in Spray-Valves for Liquid-Fuel Engines; and I do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same. i

The present invention relates to injection valves particularly adaptedfor use in a system of direct or solid fuel injection for internalcombustion engines; 6- 6., a system in which liquid fuel, such as oil,is pulverized and sprayed into a combustlon chamber without the use ofcompressed air.

To secure a sufficient degree of pulverization in systems of this type,it is necessary that the fuel be supplied through a small aperture atvery high pressure and very high,

velocity; and it has been a defect, generally speaking, of the enginesof this type which have heretofore been proposed, that the pressure atwhich the fuel is supplied has not been carried to or consistentlymaintained at the point necessary to properly atomize the fuel. As anillustration of the importance. of very high pressure of injection insuch systems, it may be stated that a certain fuel oil issuing from sucha valve under a pressure of from 2,000 to 3,000 pounds per square inchwill burn either very sluggishly or not at all when ignited by a matchin the open air. I At 4,000 pounds per square inch, this oil will burnreadily and at 6,000 pounds per square inch it will burn explosively.

If an engine of this type is to operate on the Diesel cycle, as isusually thecase, the rate of injection of the fuel must vary If thisvarying fuel feed is supplied to the combustion chamber through a valveopening of fixed size, the pressure and Velocity may be too low at thebeginning of the injection, reach a dangerously high point during themaximum rate of injection, and drop to a point below that necessary toproperly atomize the fuel at the end of the injection. It is,consequently, of great importance to provide an injection system inwhich the size of the opening is constantly proportional to the desiredrate of injection, so that the pressure and velocltles may rewell asother objects and advantages thereof main constant during the entireperiod of injection, or substantially so. 7 It is further of importanceto so construct the injection valve that the maximum surface of thepulverized fuel shall constantly be presentedto a fresh portion. of theair compressed within the combustion chamber.

These several objects are achieved, in accordance with the presentinvention, primarily by forcing the fuel into the combustion chamberunder very high pressure through an injection valve or'orifice, theopening of which is due tothe injection pressure and is opposed by thetensile strength and resistance to linear deformation of avalve-retaining member made of a metal, such as steel, having goodtensile strength and such elasticity that the high pressures ofinjection are well within the limit of elasticity of the metal. In thisway, the injection valve or orifice opens, under the very high pressureof the liquid fuel, only to a minute extent which is constantlyproportional to the applied pressure, and the liquid fuel is pulverizedto a very high degree, while the pressures and velocities of injectionremain substantially constant throughout the injection period.

The particular nature of the invention, as

will appear more clearly from a description of a preferred embodimentthereof as shown in the accompanying drawlng in which Figure 1 is asectional view taken transversely through the cylinder at the pointwhere the valve is inserted; Fig. 2 is an enlarged longitudinalsectional view taken along the line 22 of Fig. 1; Fig. 3 1s a transversesection along thellne 33 near the lower end of the valve, and Fig. 4 isa sectional view of the lower end of the Valve showing the quillsinseparated relation. Referring to the drawings in which simllar referencecharacters denote similar parts throughout the several views, the outercas- 100 ing of a cylinder of an internal combustion engine to whichliquid fuel is supplied d1- rectly is indicated at 10, and 11 indicatesthe inner wall of the cylinder forming the combustion chamber. aperturein the outer casing is the body 12 of the valve. This body is providedwith a portion 13 at its inner end of reduced diameter and which isthreaded into the inner wall 11 of the cylinder, a gasket 14 be- 1Fitted within. an

ing provided for forming a tight joint. The body 12 is provided with acentral bore within which are tightly inserted the inner members of thevalve.

These inner members comprise a pair of metallic quills 15 which are heldtogether throughout their length by a surrounding.

sleeve or jacket 16,

preferably formed of high grade spring liquid fuel to the valve underhigh pressure.

The transverse portions 19 of the quills,

. which form the closed end of the valve are normally held tightly incontact with each other by the tensile strength and the resistance todeformation of the surrounding jacket. When,however, the pressure offuel supplied by the .pump rises in the valve to a point where theresistance to the deformation of the spring-steel jacket is overcome,the tips of the two quills will separate slightly. The lower end of thebore 12 should be slightly larger than the normal outside diameter ofthe surrounding jacket as indicated at 20 to permit such expansion; andthe elastic limit of the jacket should be well above the injectionpressure. As the two quills separate under the influence of Dieselcycle,

high pressure, a narrow aperture will be formed of a size proportionateto the applied pressure and from which the fuel will issue under highpressure and at high velocity and will assume a fiat fan-shaped formwhich will cause the fuel to be sprayed in a narrow sheet across thecombustion chamber.

If the engine is one operating on the it is necessary that the rate ofinjection of fuel should be varied, but the valve of the presentinvention will automatically maintain the pressure and velocity of thefuel practically constant during injection, regardless of the rate ofinjection, for the reason that the increase of injection pressure willcause additional expansion of the jacket with a corresponding increasein the width of the slit, which will thus permit more fuel to besupplied to the cylinder without any substantial increase in thevelocity or pressure of injection. The conditions are interdependent andwork automatically to maintain constant velocity of fuel supply,regardless of the rate of inj ection, until the pressure drops belowthat predetermined point at which the valve will close. I

I claim:

1. In a system of direct fuel injection for internal: combustionengines, an injection The upper end of theholding pand under thepressure of fuel within said valve, a metallic valve retainer firmlyholding the valve closed, and means for applying liquid fuel to thevalve under a pressure sufficient to efiect the opening thereof againstthe resistance to linear deformation of the retainer but Well within thelimit of elasticity of the metal thereof, substantially as described.

2. In a system of direct fuel injection for internal combustion engines,an injection valve comprising a feed tube split at the injection end toform an injection orifice, a metallic retaining jacket surrounding thetube andfirmly holding the injecting orifice closed, and means forapplying liquid fuel to the valve under a pressure suificient to effectthe opening thereof against the resistance to expansion of the retainingjacket but well within the limit of elasticity of the metal thereof.

3. A valve for injecting liquid fuel into the cylinder ofan internalcombustion engine comprising a pair of symmetrical members forming atube normally closed at one end and open at the other end for theadmission of liquid fuel, an expansible jacket surrounding said membersand normally them in contact but adapted to exmembers to permit them toseparate at the normally closed end to form a narrow slit through whichfuel may be injected into the cylinder.

4. A valve for injecting liquid fuel into the cylinder of an internalcombustion engine comprising a pair of symmetrical members forming atube normally closed at one, end and open at the other end for theadmission of liquid fuel, an expansible jacket surrounding said membersand normally holding them in contact but adapted to expand under thepressure of fuel within said members to permit them to separate at thenormally closed end to form a narrow slit through which fuel may beinjected into the cylinder, and a body member into which the .7

tube and the jacket are tightly fitted and provided with clearance topermitexpansion of the jacket and separation of the members at thenormally closed end of the tube.

5. A valve for injecting liquid fuel into the cylinder of an internalcombustion engine comprising a tubular member open at one end andnormally closed but divided transversely at the other end, an.expansible jacket surrounding said tubular member and normally holdingthe divided end thereof closed, but adapted to expand under pressure offuel within said member to permit the portions thereof to separate atthe normally closed end to form a narrow slit through which fuel may beinjected into the comprising a tubular member open atone end andnormally closed but divided transversely at the other end, an expansiblejacket surrounding said tubular member and normally holding the dividedend thereof closed, but adapted to expand under pressure of fuel withinsaid member to permit the portions thereof to separate at the normallyclosed end to form a narrow slit 10 through which fuel may be injectedinto the cylinder of the engine, and a body portion provided with acentral bore within which the tubular member and the surrounding jacketare inserted, said bore being of slight- 1y greater diameter than thejacket at the closed end of the tubular member to allow the jacket toexpand and open the normally v

